I think it's simple. If the test is valid, then use it for everyone. If it is not valid, then either use one that is valid, or don't use it for anyone. For a school district or court system to make a decision that a test is not valid for everyone, so we'll only test the group of people where it is valid, but still use it as entry criteria for specific programs, is absurd. It's just a case of people making bad decisions based on partial information. They need to find people who can both find all the relevant information, and then have the ability to make an informed decision based on the information. Anything else makes the American public school system look like a farce. Oh yeah, it is. (OK, not everywhere, but in most places).